Electrical fitting.



Patented Oct. 2, I900.

w. T. PRINGLE.

ELECTRICAL FITTING.

(Application filed Feb. 12, 1900.

3 Sheets$hoet I.

(No Model.)

m W5} mmm w f w No. 658,924. Patented Oct. 2, I900. W. T. P'RINGLE.

ELEGTRICALHTTING.

(Application med Feb. 12, 1900.

3 Sheets-Sheei 2.

No. 658,924. Patented Oct. 2. I900.

Y W. T. PRINGLE.

ELECTRICAL FITTING.

(Applicnt'xon filed Feb. 12, 1900) (No Model.) 3 Sheets- 6M 3.

FIG. 7

FIG. 6.

WITNESSES: INVENTOR:

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UNITED STATES PATENT ()EEICE.

WILLIAM T. PRINGLE, OF LANSDOVNE, PENNSYLVANIA.

ELECTRICAL FITTING.

SPECIFICATION forming part of Letters Patent No. 658,924, dated October 2, 1906-.

Application filed February 12, 1900. fierial No.4,910. (No model.)

To all whom it may concern:

Be it known that 1, WILLIAM T. PRINGLE, of Lansdowne, in the State of Pennsylvania, have invented certain new and useful Improvements in Electrical Fittings, whereof the following is a specification, reference being had to the accompanying drawings.

My invention relates to that general class of electrical fittings designed for temporarily connecting a light, motor, electrical heater, or similar device with a supply of current.

i Such a fitting comprises two complementary parts-first, a fixed receptacle inclosing the terminals of an electrical supply-circuit, and, second, an attachment-plug containing the terminals of the local circuit of the device to be supplied, said plug being portable and so arranged as to be readily inserted and removed with respect to said receptacle.

My improvements have to do with a peculiar type of attachment-plug, comprising two distinct partsfirst, a tubular handle member, which projects exterior to the receptacle when the plug is in cooperative relation therewith, by which the plug may be manipulated and through which the local-circuit conductors are extended, and, second, a diaphragm provided with seats for the respective terminals of said conductors arranged to extend between and insulate said terminals within said receptacle.

The National Board of Fire Underwriters has specified porcelain as the proper insulating material for all fittings of the general class to which the present invention relates.

lIowever, said board has recognized that as are not only advantageous in that the ceramic plug affords a superior non-combustible insulatingbase for the local terminal-s seated thereon, but the cost of manufacture of the ceramic plug, as herein set forth, is less than one-fifth the cost of man ufacture of the afore said ordinary plug formed of combustible ma terial.

In the accompanying drawings, Figures 1 and 2 show an attachment-plug conveniently embodying my invention assembled in cooperative relation with a complementary receptacle. Figs. 3, t, 5, and 6 are detail views of the form of attachment-plug shown in Figs. 1 and 2, Figs. 3 and 4 being respective side and edge views thereof, Fig. 5 being a sectional view taken on the line 5 5 in Fig. 3, and Fig. 6 a cross-sectional view taken on the line 6 6 in Fig. 5. Fig. 7 is a sectional view showing the essential elements of a die-mold wherein my improved plug may be conveniently formed, and Fig. 8 is a plan view of a part of the mold shown in Fig. 7.

It is preferable that an attachment-plug of the type to which this invention relates should be symmetrically formed, so that the localcircuit terminals which are embodied therein may be reversed with respect to the supplycircuit terminals in its complementary receptacle merely by reversal of the position of the plug. Therefore I have shown an attachment-plug having its various parts symmetrically arranged, the handle member thereof being provided with a central passage-way for the conductors of the local circuit, and said passage-way being opposed by a central diaphragm upon whose opposite sides the respective conductors are secured in symmetrical relation, as hereinafter set forth.

Referring to Figs. 1 and 2, A is the seat portion or member of an attachmentplug provided with insulated seats a d for the terminals b b of the local-circuit conductors B B. Said conductors extend through the tubular passage-way (t in the handle portion of member A of said plug, and said passage-way being obstructed by the central diaphragm (t of said seat member said conductors extend through the laterally-disposed passage-way a" to their points of secureinent upon said diaphragm. As a matter of convenience I prefer to connect said conductors indirectly to their terminals Z) I) by means of the fusewires 5 b the connection between said conductors and said fuse-wires being made upon plates b If, fixed upon the opposite faces of the diaphragm.

The receptacle 0, which is complementary to the attachment-plug above described, is provided, as shown in Figs. 1 and 2, with op posed terminals 61 d of the conductors D D of the electrical supply-circuit, and the front plate C of said receptacle comprises a hinged door (1', which may be closed when the attachment-plug is Withdrawn. The arrangement of the parts aforesaid is such that the depth of insertion of the plug member A within said receptacle (J is limited by the shoulder or ridge to at the junction of said seat member of the plug with the handle member A thereof.

Referring to Figs. 3 to 6, inclusive, it may be seen that the arrangement of the diaphragm a in axial alinement with the tubular handle member A is such as to afford the most effective insulation of the various elements of the circuit secured upon the opposite sides thereof in symmetrical relation, the seats a being formed by marginal flanges projecting from the recessed diaphragm a so as to inclose and protect the fuse-wires secured thereon, although the terminals 1) Z) are exposed upon said seats an to insure the maximum area of contact with the terminals (1 d, fixed in the receptacle. In the latter figures I have shown the several smaller apertures and recesses for the fastenings, which serve to maintain the terminals, fuses, &c., in the assembled relation shown in Figs. 1 and 2. However, such details are not of the essence of the present invention and may be understood without further description.

A plug having its component parts arranged as hereinbefore described may be readily formed as a casting of fusible material, such as the imitation-rubber compound aforesaid. It is to be understood, however, that the ceramic material aforesaid may not be thus fused and cast, but must be molded by compression from what are termed clay crumbs and after compression be baked to secure the desired cohesion of its component particles. Therefore I have shown. in Figs. 7 and 8 means for-conveniently molding my improved form of plug from the crumbs aforesaid. Referring to said figures, E is the stationary member of the mold, the interior of which is of the outline shown in Fig. 3. The lower half of the contour of the plug shown in section in Fig. 5 is formed by the head F of the plunger F, which is of the outline of the mold member E and is normally stationary therein, and the upper contour of said plug is formed by the head G of the main plunger G. The opening (shown in Fig. 5,) extending through the plug-diaphragm a is formed by the vertical stud E, which projects from the bottom of the mold member E in fixed relation therewith, and similar openings through said diaphragm for the reception of screws, 850., are formed by similar studs projecting from said mold. The conductor passage-Way a (shown in Fig. 5,) extending through the handle member A of the plug in alinement with said diaphragm a", is formed by the core-stem H, which is arranged to reciprocate through the side wall of the mold member E, as shown in Fig. 7, and is provided at itsv inner extremity with the tongue 72, fitted to a corresponding aperture in the stud E. The operation of said molding device is as follows: In the initial position of the parts the core-stem H and the plunger G are Withdrawn from the mold E, and the first step in the operation is to advance the core-stem to engagement with the stud E, as shown in Fig. 7. A predetermined quantity of clay crumbs is then deposited within the mold E, and said crun'ibs are manually compressed by means of a suitable implement between said core-stem H and the upper face of the plunger-head F. The plunger G is then lowered until the crumb contents of the mold E are compressed, as shown in Fig. 7, whereupon said corestem His withdrawn from the mold E and said plunger G is uplifted. The molded plug being then free to be uplifted from the mold E is conveniently discharged therefrom by upward movement of the plunger F, whereupon the latter is lowered and the aforesaid operation repeated.

I am aware, as hereinbefore stated, that fittings of the general class to which my invention relates have been heretofore provided with insulating porcelain bases, and it is to be understood that my present invention is limited to an attachment-plug of the particular type herein defined. On the other hand, I do not desire to limit myself to the precise form of plug which I have chosen for illustration, as it is obvious that various modifications maybe made therein without departing from the spirit of my invention.

I claim- 1. An article of manufacture consisting of an electrical attachment-plug formed of ceramic, comprising a member provided with insulated seats for the respective terminals of an electric circuit, a handle member in intogral relation with said seat member, and a conductor passage-way opening through said handle member, and terminating in a lateral opening intermediate of said handle and said seat member, substantially as set forth.

2. An article of manufacture consisting of an electrical attachment-plug formed of ceramic, comprising a member provided with insulated seats for the respective terminals of an electric circuit, a handle member in integral relation with said seat member, and a conductor passage-way opening through said handle member, and terminating in lateral openings intermediate of the length of the plug, substantially as set forth.

3. An article of manufacture consisting of:

an electrical attachment-plug formed of ceramic, comprising a recessed diaphragm provided upon its opposite sides with insulated seats for the respective terminals of an electrical circuit; a handle member distinct from said seat member; a conductor passage-way extending through said handle member in alinement with said diaphragm; and a conductor passage-way extending through said diaphragm at right angles with the first passage-Way aforesaid, substantially as set forth.

4:. An article of manufacture consisting of an electrical attachment-plug formed of ceramic, comprisinga diaphragm provided with insulated seats for the respective terminals of an electrical circuit; a handle member separated from said seat member by ashoulder or ridge; a conductor passage-Way extending through said handle member in alinement with, and obstructed by, said diaphragm; and lateral openings in the opposite faces of said diaphragm at the termination of said passageway, substantially as set forth.

5. An article of manufacture consisting of an electrical attachment-plug formed of ceramic,com prising a diaphragm provided upon its opposite sides with seats for the respective terminals of an electrical circuit, comprising marginal flanges at the edges of said diaphragm a handle memberin integral relation with said seat member; and a conductor pasber, and terminatingin lateral openings in respective opposite faces of said seat member, substantially as set forth.

7. The herein-described process of molding an electrical attachmentplug of ceramic, which consistsin manually adj usting the mass of clay crumbs around a core-stem, subjecting said mass to pressure in a direction sub stantially at right angles with the axis of said core-stem, Withdrawing said core-stem While said mass is under pressure and subsequently removing said pressure, substantially as set forth.

WILLIAM T. PRINGLE.

Witnesses:

ARTHUR E. PAIGE, E. L. FULLERTON. 

